Expression and characterization of bifunctional fusion proteins possessing antitumor and thrombolytic function for targeting therapy.

It is a usual clinical phenomenon that cancer patients are prone to thrombosis. Until now, there have been no efficient methods or appropriate drugs to prevent and cure tumor thrombus. ΔSEC2, N-terminal deletion of 17 amino acids and C-terminal deletion of 132 amino acids, retained antitumor activity of SEC2. ΔSak, N-terminal deletion of 10 amino acids, had thrombolytic activity and specificity advantages. By utilizing bioactivities of ΔSEC2 and ΔSak, ΔSEC2-ΔSak and ΔSak-ΔSEC2 were constructed. Octreotide is a tumor targeting peptide and it can be combined with somatostatin (SST) receptors of tumor surface in ligand-receptor binding way. It can be used to increase specificity for tumor therapy. Based on previous studies, DNA sequence encoding octreotide gene was inserted into plasmid pET-28a-Δsec2-Δsak and pET-28a-Δsak-Δsec2. After expression and purification, fusion proteins could significantly stimulate proliferation of mouse spleen lymphocyte, obviously inhibit the growth of human gastric carcinoma BGC-823, and have thrombolytic activity, indicating that fusion proteins retained bioactivities of staphylococcal enterotoxin C2 and Sak. Furthermore, tumor binding capacity of fusion protein was confirmed through the coimmunoprecipitation method. The result showed that they could bind SST receptor 2 antibody, indicating that fusion proteins could be specifically targeted to tumor surface. It has important significance and may be used for targeted therapy.

Construction of novel chimeric proteins through the truncation of SEC2 and Sak from Staphylococcus aureus.

It is an usual clinical phenomenon that cancer patients are prone to thrombosis. Until now, there have been no efficient methods or appropriate drugs to prevent and cure tumor thrombus. Therefore, the construction of a bifunctional chimeric protein for the treatment of cancer, complicated with thrombosis, is of great significance. Utilizing the superantigenic activity of staphylococcal enterotoxin C2 (SEC2) and the thrombolytic activity of staphylokinase (Sak), Sak-linker-SEC2 and SEC2-linker-Sak were constructed which had good anti-tumor and thrombolytic activities at the same time. Due to the intrinsic emetic activity of SEC2 and high molecular weight (MW) of chimeric proteins (44 kDa), their clinical applications will be restricted. In this study, novel chimeric proteins including ΔSEC2-ΔSak and ΔSak-ΔSEC2 were constructed through the truncation of SEC2 and Sak without 9-Ala linker and His-tag. Compared with the former, both the truncated proteins preserved nearly the same anti-tumor and thrombolytic activities. In addition, their MWs were only 29 kDa and their immunoreactivities were slightly lower than that of Sak-linker-SEC2 and SEC2-linker-Sak, respectively. Therefore, the novel chimeric proteins possessed merits and characteristics, such as low MS, low immunogenicity, and difunctionality which the former had not. It will be of great interest if the above-mentioned proteins can be used to cure Trousseau syndrome in clinic.

Effect of ulinastatin, a human urinary protease inhibitor, on heatstroke-induced apoptosis and inflammatory responses in rats.

Ulinastatin has been demonstrated to protect against heatstroke by reducing cerebral ischemia and damage in rats. In order to extend these observations, apoptosis and systemic inflammatory responses were assessed in rats treated with ulinastatin prior to the initiation of heatstroke. Following the onset of heatstroke, histological analysis revealed that the hippocampal tissues displayed edema and damage. In addition, upregulation of malondialdehyde, inducible nitric oxide synthase (iNOS) and reactive oxygen species and downregulation of superoxide dismutase were observed compared with the respective levels in the control group. Furthermore, TUNEL staining and western blotting assays indicated that heatstroke induced cell apoptosis by increasing the Bax/Bcl-2 ratio and caspase-3 levels, and upregulating the protein expression levels of nuclear factor-κB, cyclooxygenase-2 and iNOS. However, the injury induced by heatstroke was significantly inhibited by ulinastatin pretreatment at doses of 5,000 and 10,000 IU/kg. Survival analysis of the rats subjected to heatstroke demonstrated that rats treated with ulinastatin at a dose of 10,000 IU/kg lived longer than those that did not receive ulinastatin treatment. These observations indicate that ulinastatin may protect against heatstroke by reducing apoptosis and systemic inflammatory responses.

miR-106a promotes growth and metastasis of non-small cell lung cancer by targeting PTEN.

MicroRNAs are a class of small non-coding RNAs that play essential roles in cancer development and progression. Recent studies suggested that abnormal expression of miRNAs occurs frequently in non-small cell lung cancer (NSCLC) tissues compared to adjacent normal tissues. In this study, we investigated the expression and the biological roles of miR-106a in non-small cell lung cancer. Our results showed that miR-106a was up-regulated in NSCLC tissues and cell lines. Inhibition of miR-106a in NSCLC cells substantially inhibited cell proliferation, migration, and invasion. Phosphatase and tensin homolog (PTEN) was identified as a direct target of miR-106a, and over-expression of miR-106a suppressed PTEN by direct binding to its 3'-untranslated region (3'-UTR). Furthermore, the presence of miR-106a was inversely correlated with PTEN in NSCLC tissues. Overall, this study suggested that miR-106a inhibited the growth and metastasis of NSCLC cells by decreasing PTEN expression. These data provide novel insights with potential therapeutic applications for the treatment of NSCLC.

Cyclooxygenase-2 inhibition as a strategy for treating gastric adenocarcinoma.

Cyclooxygenase-2 (COX-2) has been proven to play critical roles in inflammation as well as in cancer. Some studies have shown that the anti-inflammatory, immunosuppressive and anti-arthritic effects of celecoxib are mainly attributed to the inhibition of COX-2 expression. The present study aimed to investigate the function of COX-2 in human gastric adenocarcinoma (GAC). Forty-five cases of human GAC tissues and corresponding adjacent non-cancerous tissues (ANCTs) were collected. The expression of COX-2 and proliferating cell nuclear antigen (PCNA) was assessed using immunohistochemical assay through a tissue microarray procedure. GAC cells (SGC-7901 and MKN-45) in vitro were treated with COX-2 siRNA or different concentrations of celecoxib to observe their effects on cell proliferation, invasion and the underlying molecular mechanisms. As a consequence, the expression of COX-2 and PCNA was found in cancer tissues with a higher strong reactivity rate, compared with the ANCTs (80.0 vs. 53.3%, P=0.011; 68.9 vs. 48.9%, P=0.047), and COX-2 was positively associated with lymph node metastasis of GAC patients (P=0.011). Targeted knockdown of COX-2 inhibited the proliferation, migration and invasion of GAC cells with decreased expression of PCNA. COX-2 inhibitor celecoxib also suppressed the proliferative activities of GAC cells with decreased expression of COX-2 and PCNA. In addition, the tumor volume in the MKN-45 subcutaneous tumor model treated with siCOX-2 was significantly smaller than that of the negative control (NC) group (P<0.01). Taken together, our findings offer a strong preclinical rationale to target COX-2 signaling as a therapeutic strategy to improve the treatment of gastric adenocarcinoma.

LncRNA HMlincRNA717 is down-regulated in non-small cell lung cancer and associated with poor prognosis.

INTRODUCTION: Long non coding RNAs (lncRNAs) have emerged recently as major players in tumor biology and may be used for cancer diagnosis, prognosis, and potential therapeutic targets. The lncRNA HMlincRNA717, a newly identified lncRNA, was demonstrated to be down-regulated in gastric cancer. However, little is known about its role in non small cell lung cancer (NSCLC). METHODS: Expression of lncRNA HMlincRNA717 in tumor and their matched non-tumor tissues was determined by quantitative real-time PCR (qRT-PCR) in NSCLC patients. Then, we analyzed the potential relationship between lncRNA HMlincRNA717 expression levels in tumor tissues and clinicopathological features of NSCLC, and clinical outcome. RESULTS: lncRNA HMlincRNA717 expression level was significantly decreased in NSCLC tissues in comparison to adjacent non-tumor tissues. It was also proved that HMlincRNA717 expression was to be associated with NSCLC histological grade, and lymph node metastasis. In addition, survival analysis proved that down-regulated HMlincRNA717 expression was associated with poor overall survival of NSCLC patients. Multivariate survival analysis also proved that HMlincRNA717 was an independent prognostic factor for NSCLC patients. CONCLUSIONS: The present study showed the down-regulation of HMlincRNA717 and its association with tumor progression in human NSCLC. It also provided that HMlincRNA717 expression was an independent prognostic factor for patients with NSCLC, which might be a potential prognostic biomarker and therapeutic target for NSCLC.

[Synthesis of medium-chain-length polyhydroxyalkanoate (mcl PHA) in type I PHA synthase negative mutant of Aeromonas hydrophila].

Aeromonas hydrophila CGMCC 0911 possessing type I polyhydroxyalkanoate (PHA) synthase gene (phaC) only accumulate copolyesters consisting of 3-hydroxybutyrate (3HB) and 3-hydroxyhexanoate (3HHx), abbreviated as PHBHHx, from lauric acid as sole carbon source but not from glucose. The gene encoding type I PHA synthase was interrupted by insertion of a chloramphenicol resistance gene (Cm). Conjugation of suicide plasmid pFH10 transformed A. hydrophila CGMCC 0911 into a recombinant organism with the disrupted type I PHA synthase gene (phaC:: Cm) , through an in vivo homologous recombination process, type I phaC of A. hydrophila genome was replaced by the disrupted phaC, and Cm gene was integrated into the genome of A. hydrophila, resulting in type I phaC-negative mutant, which was proved by DNA sequencing. Results of GC analysis showed that this mutant could not accumulate PHBHHx again but accumulate medium-chain-length (mcl) PHA from lauric acid or glucose as carbon source, clearly indicating the existence of another type I PHA synthase in the wild type A. hydrophila. It will play its function and accumulate mcl PHA only when type I PHA synthase was inactivated. into the genome of A. hydrophila, resulting in type I phaC-negative mutant, which was proved by DNA sequencing. Results of GC analysis showed that this mutant could not accumulate PHBHHx again but accumulate medium-chain-length (mcl) PHA from lauric acid or glucose as carbon source, clearly indicating the existence of another type II PHA synthase in the wild type A. hydrophila. It will play its function and accumulate mcl PHA only when type I PHA synthase was inactivated.